Sir Beryth, the Valiant

Vigilance
Charge—Whenever Sir Beryth, the Valiant attacks,
if another Knight you control is attacking, exile
the top card of your library. If that card is a Knight,
you may cast it without paying its mana cost.
Whenever a Knight enters the battlefield under your control, put a +1/+1 counter on Sir Beryth, the Valiant. He gains indestructible until end of turn.
He always led the charge. And the other knights always heeded his call.